The NHN herbarium database incorporates data from various sources. A majority of records relate to specimens held at one of the NHN herbaria (AMD, L, U & WAG). The database also contains records of duplicates sent to other herbaria, specimens databased for taxonomic revision or from areas of special interest to NHN, for instance Gabon.

The four NHN herbaria each have their own focus. Leiden (L) is by far the largest of the three, with c.4 million specimens, is well-known for its extensive collections from South-East Asia, especially from Indonesia and New Guinea. It also holds a large collection of palearctic plants and is the principal herbarium for Dutch plants. As the oldest Dutch herbarium, it also contains several historic collections, some of them probably the oldest herbarium collections still in existence.

The former herbarium of Utrecht University (U), has a strong focus on tropical America, especially the Guianas and the Netherlands Antilles. It has around 700,000 collections.

The former herbarium of the Biosystematics Group of Wageningen University (WAG) houses c. 900,000 specimens. It focuses on tropical Africa, with particular emphasis on material from the rain forests of west and central Africa, but it also holds an important collection of Ethiopian plants. Since Wageningen has its origin in an Agricultural University, WAG also contains many cultivated plants. WAG contains one historical collection that is curated separately: The Clifford Herbarium.

This website provides access to the NHN herbarium specimens and images. The NHN (Nationaal Herbarium Nederland) originated as a cooperation of the 3 major herbaria of the Netherlands (L, U & WAG), and is now the botanical part of Naturalis Biodiversity Center.